As the conventional vessel of this type, there is known the one illustrated in FIG. 1A. This vessel 1 includes a square dish-shaped vessel body 2 which is opened at the upper part and provided with an outwardly projecting flange 3 at the peripheral edge portion of the opening. A toner 4 is received in this vessel body 2. A twice-folded cover sheet 5 comprises a lower part 6 and an upper part 7, the former covering the opening, the latter, which is superposed on the former, extending its fore end part 8 outside of the flange 3.
When supplying the toner 4 in the developing area of the copying machine (not shown) by using the toner vessel of this type, the toner vessel is turned upside down, as shown in FIG. 1B, and applied to a copying machine for use. The sheet 5 is peeled off from the flange 3 by pulling the sheet in the direction of the arrow with the end part 8, and thus the opening of the body 2 is gradually opened, whereby the toner 4 is allowed to fall into the developing area of the copying machine.
The conventional vessel of this type, however, was defective in that upon peeling the lower part 6 of the sheet 5 from the flange 3, the part 6 must be pulled out of the vessel 2, but the toner 4' adhered to the back of the lower part 6 comes to fall, at that time, inside or outside of the copying machine other than its developing area, thereby staining those parts.
In view of this, the assignee of the invention disclosed in this application has proposed a toner vessel, which is capable of eliminating the above mentioned disadvantage. The aforesaid application U.S. Ser. No. 527,132, has previously been assigned to the assignee of the present application.
The thus proposed toner vessel is the one illustrated in FIG. 2A, which will be explained in such a manner that the same reference numerals are attached to the same components as the prior art for the purpose of omitting the description thereof. The detailed description contained herein is directed mainly to the Applicant's improvement.
On the upper portion 7 of the sheet 5 is disposed the cover plate 9. Both its side flanges are bent inside to form bent portions 10. Both side flanges 3 are fitted in groove portion formed by said bent portions 10. The plate 9 is designed to be movable along the flanges 3 in the horizontal direction. The slit 11 is provided near the rear end of the plate 9. The upper portion 7 of the sheet 5 is folded back upwards at the forward end of the plate 9 and further inserted inside from this slit 11, thereby pulling the end portion 8 outside along the upper surface of the lower portion 6.
The method of using this toner vessel is shown in FIG. 2B, wherein when pulling the sheet in the direction of the solid arrow with the end portion 8, the upper portion 7 of the sheet 5 is first pulled out of the vessel 2 together with the plate 9, and when further pulling the sheet 5 while holding the plate 9 in place, the toner-free upper portion 7 is pulled out of the plate 9 and at the same time the toner-adhered lower portion 6 is peeled off from the vessel 2 and pulled out on the back of the plate 9. In this case, the toner 4 adhered to the lower portion 6 is stripped off by the flange to the slit 11 and is deposited into the developing area, and the remaining adhering toner 4 sometimes falls down on the back of the plate 9 but never falls into other places outside the developing areas. After the toner within the vessel 2 has wholly been deposited in the developing area, the plate 9 is moved in the direction of the dotted arrow to cover the vessel 2. The toner vessel and plate assembly are then removed from the copying machine. Thus, the environmental pollution caused by the toner falling outside the developing area can be prevented.
The toner vessels illustrated in FIG. 2A and FIG. 2B are as explained above, and are superior to those illustrated in FIG. 1A and FIG. 1B. Nevertheless, the former vessels had disadvantages in that removing the toner from the lower portion of the sheet 6 was not fully satisfactory.